1. Field of the Invention
This invention relates generally to seawater powered tools. In particular, this invention relates to a rotary impact tool which utilizes pressurized seawater as the hydraulic operating fluid.
2. Description of the Prior Art
Conventional underwater tools are underwater pneumatic tools, underwater oil hydraulic tools and underwater electric tools which respectively utilize pressurized air, pressurized oil and electric power for motive power. Such conventional underwater tools have certain disadvantages.
In the underwater pneumatic tools, the air is usually exhausted into the surrounding water so that the depth at which the underwater pneumatic tool can be used is limited due to back pressure on the discharged air. Moreover, large quantities of bubbles are generated so that visibility in the water is disturbed and in some cases, the use of acoustic communication through the water is disturbed.
The use of oil driven hydraulic tools underwater creates serious logistics problems in that large quantities of oil have to be shipped and stored at sea. There is also a need for supply and return hoses from a surface ship limiting the diver's ability to handle the hydraulic tool, particularly where heavy surge and strong currents exist. Further, leakage of the oil fluid from the tool would contaminate the environment.
In underwater electric tools, electrical leakage into the water can occur so that it is dangerous for the diver to operate the tool underwater.
Another alternative would be to design a hydraulic tool which utilizes pressurized seawater as the operating fluid. The design of a tool which utilizes seawater as the hydraulic fluid presents a serious challenge to the designer because of the general corrosiveness of seawater on precision made parts in such tools. The poor lubricity of seawater and much lower viscosity for seawater than for conventional oil hydraulic fluid contributes to the problem of designing an efficient seawater operated hydraulic tool.
With the disadvantages inherent in the design of oil operated tools, air operated tools and electrically powered tools when utilized in an underwater environment the present invention was conceived and one of its objectives is to provide a rotary impact tool for use in an underwater environment, which utilizes seawater as the operating fluid and provides satisfactory results for the user.
It is another object of the present invention to provide a rotary impact tool which utilizes seawater as the hydraulic fluid so as not to contaminate the environment.
Various other advantages and objectives of the present invention will become apparent to those skilled in the art as a more detailed description of the invention is set forth below.